There is a stored Cross-site Scripting vulnerability in Esri Portal for ArcGIS Enterprise versions 10.8.1 – 10.9.1 that may allow a remote, authenticated attacker to create a crafted link that is stored in the Layer Showcase application configuration which when clicked could potentially execute arbitrary JavaScript code in the victim’s browser. The privileges required to execute this attack are high. The attack could disclose a privileged token which may result in the attacker gaining full control of the Portal.